PARENTERAL NUTRITION
Parenteral nutrition (PN) is a type of nutrition support that relies on the intravenous
administration of nutrients to patients who are unable or unwilling to take adequate
nutrition orally or enterally.
PN may be used as an addition to an oral diet or enteral nutrition (EN) in order to meet
needs, as the sole source of nutrition during recovery from illness or injury of the
gastrointestinal (GI) tract, or as a long-term life-sustaining therapy for patients who have
compromised ability to enterally absorb nutrients.
Parenteral Nutrition Administration
1. Central Parenteral Nutrition
● In central PN, venous access is acquired in a central vessel.
● In central PN, the catheter tip is located in a large, high-flow vessel, typically the
junction of the superior vena cava and right atrium.
● The ideal tip location is the lower third of the superior vena cava or at the atrio-caval
junction, as these locations are associated with the fewest mechanical and
thrombotic complications.
● There are two main types of central access: short-term and long-term central venous
catheters (CVCs).
● Short-term CVCs, often referred to as non-tunneled catheters, vary by insertion site
and may be inserted in the subclavian, internal or external jugular,
● or femoral veins.
● Long-term central access seeks to separate the skin from the venous entry site in
order to reduce infection risk. Long-term CVCs are often referred to as tunneled
catheters as they are tunneled under the skin to the venous site although the
catheter exits through the skin.
● Central PN is usually the preferred form of access because it allows greater flexibility
in the types of PN infusions that can be administered.
2. Peripheral Parenteral Nutrition
● In peripheral access, the catheter tip is located outside of a central vessel.
● Peripheral PN is usually selected because it is a safer and easier way to access the
vasculature, particularly for short-term use.
● Peripheral PN is typically used for a maximum of 2 to 6 weeks at a time.
● An advantage of peripheral PN is that there is evidence that it is associated with a
lower risk catheter-related infections, but this may be due to the shorter dwell time.
● Because peripheral PN infuses into the smaller veins of the extremities, the PN
formula cannot be as hypertonic as those formulas used in central PN.
● Formulas should be of low osmolarity, defined as <900 mOsm/L.
● Formulas of higher osmolarity do not increase the risk of phlebitis in the short term,
but these formulas may cause a burning sensation.
, Indications and contraindications
Common indications for Parenteral Nutrition
● Patient has failed EN with appropriate tube placement
● Severe acute pancreatitis
● Severe short bowel syndrome
● Mesenteric ischemia
● Paralytic ileus
● Small bowel obstruction
● GI fistula unless enteral access can be placed distal to the fistula or where volume of
output warrants trial of EN
Contraindications include
● Functional and accessible GI tract
● Patient is taking oral diet
● Prognosis does not warrant aggressive nutrition support (terminally ill)
● When risk exceeds benefit
● Patient expected to meet needs within 14 days
Parenteral Nutrition Formulation
Parenteral nutrition is a hypertonic solution made up of, but not limited to, carbohydrate in
the form of dextrose, crystalline amino acids, lipid emulsions, vitamins, minerals, and sterile
water.
1. Carbohydrates
● The most commonly used carbohydrate substrate used in PN formulas is dextrose
monohydrate.
● In its hydrated form, dextrose provides 3.4 kcal per gram.
● Commercially, dextrose is available in multiple concentrations ranging from 5% to
70%.
● Because dextrose is an acidic molecule, the higher concentration solutions are more
acidic.
● Infusing dextrose directly into the bloodstream directly raises serum glucose, which
commonly leads to hyperglycemia.
● The most common dextrose solution used in parenteral nutrition is 50% dextrose in
water (D50W).
2.Amino acids
● Amino acids are supplied through PN in their crystal- line form.
● If oxidized for energy, crystalline amino acids supply 4 kcal per gram.
● Amino acid solutions are available in different concentrations ranging from 3% to
20%.
● Commercially available amino acid solutions - 38% and 57% of total amino acids.
Parenteral nutrition (PN) is a type of nutrition support that relies on the intravenous
administration of nutrients to patients who are unable or unwilling to take adequate
nutrition orally or enterally.
PN may be used as an addition to an oral diet or enteral nutrition (EN) in order to meet
needs, as the sole source of nutrition during recovery from illness or injury of the
gastrointestinal (GI) tract, or as a long-term life-sustaining therapy for patients who have
compromised ability to enterally absorb nutrients.
Parenteral Nutrition Administration
1. Central Parenteral Nutrition
● In central PN, venous access is acquired in a central vessel.
● In central PN, the catheter tip is located in a large, high-flow vessel, typically the
junction of the superior vena cava and right atrium.
● The ideal tip location is the lower third of the superior vena cava or at the atrio-caval
junction, as these locations are associated with the fewest mechanical and
thrombotic complications.
● There are two main types of central access: short-term and long-term central venous
catheters (CVCs).
● Short-term CVCs, often referred to as non-tunneled catheters, vary by insertion site
and may be inserted in the subclavian, internal or external jugular,
● or femoral veins.
● Long-term central access seeks to separate the skin from the venous entry site in
order to reduce infection risk. Long-term CVCs are often referred to as tunneled
catheters as they are tunneled under the skin to the venous site although the
catheter exits through the skin.
● Central PN is usually the preferred form of access because it allows greater flexibility
in the types of PN infusions that can be administered.
2. Peripheral Parenteral Nutrition
● In peripheral access, the catheter tip is located outside of a central vessel.
● Peripheral PN is usually selected because it is a safer and easier way to access the
vasculature, particularly for short-term use.
● Peripheral PN is typically used for a maximum of 2 to 6 weeks at a time.
● An advantage of peripheral PN is that there is evidence that it is associated with a
lower risk catheter-related infections, but this may be due to the shorter dwell time.
● Because peripheral PN infuses into the smaller veins of the extremities, the PN
formula cannot be as hypertonic as those formulas used in central PN.
● Formulas should be of low osmolarity, defined as <900 mOsm/L.
● Formulas of higher osmolarity do not increase the risk of phlebitis in the short term,
but these formulas may cause a burning sensation.
, Indications and contraindications
Common indications for Parenteral Nutrition
● Patient has failed EN with appropriate tube placement
● Severe acute pancreatitis
● Severe short bowel syndrome
● Mesenteric ischemia
● Paralytic ileus
● Small bowel obstruction
● GI fistula unless enteral access can be placed distal to the fistula or where volume of
output warrants trial of EN
Contraindications include
● Functional and accessible GI tract
● Patient is taking oral diet
● Prognosis does not warrant aggressive nutrition support (terminally ill)
● When risk exceeds benefit
● Patient expected to meet needs within 14 days
Parenteral Nutrition Formulation
Parenteral nutrition is a hypertonic solution made up of, but not limited to, carbohydrate in
the form of dextrose, crystalline amino acids, lipid emulsions, vitamins, minerals, and sterile
water.
1. Carbohydrates
● The most commonly used carbohydrate substrate used in PN formulas is dextrose
monohydrate.
● In its hydrated form, dextrose provides 3.4 kcal per gram.
● Commercially, dextrose is available in multiple concentrations ranging from 5% to
70%.
● Because dextrose is an acidic molecule, the higher concentration solutions are more
acidic.
● Infusing dextrose directly into the bloodstream directly raises serum glucose, which
commonly leads to hyperglycemia.
● The most common dextrose solution used in parenteral nutrition is 50% dextrose in
water (D50W).
2.Amino acids
● Amino acids are supplied through PN in their crystal- line form.
● If oxidized for energy, crystalline amino acids supply 4 kcal per gram.
● Amino acid solutions are available in different concentrations ranging from 3% to
20%.
● Commercially available amino acid solutions - 38% and 57% of total amino acids.
